What is Artificial Rainfall ?

“Rainfall”, the most beautiful gift of nature. When it pours, we tend to sit back , relax and enjoy the melody of water drops falling on the ground. Rainfall is one of the necessities for all living beings on earth to survive. In the recent past, due to ecological imbalance, chopping of trees & increase in pollution, the amount of rainfall received each year is alarmingly going down. No. of countries have to encounter the situation of drought which causes extreme shortage of water essential for human beings and plants. What is someone says, rainfall is not only natural rather it can artificially made to happen. You would find it hard to believe , isn’t it. But it is true. There exist something known as Artificial Rainfall.

To tackle this situation of drought, technology is being used to increase the amount of rainfall especially in the regions which are facing scarcity of rain. This concept of using technology to cause the rainfall is known as artificial rainfall.

Artificial Rainfall:

Artificial Rain is the use of technology to cause rain. External agents such as chemicals are sprayed on the clouds to create more ice crystals and cause more moisture out of the clouds. It is effective way to increase the amount of rainfall by 15-20%.
There are three stages involved in the formation of artificial rain. Lets take a look at them.

Agitation:

Just like natural rain, the presence of cloud is necessary requirement to cause the rain artificially. Agitation is the first stage where the focus is on building up the clouds. Chemicals such as calcium oxide, calcium carbide , urea, compound of salt absorb the water vapor from he air mass and stimulate the air mass upwind to form clouds.

Building-up stage:

Second stage is the building-up stage which focuses on increasing the density of the clouds. Chemicals like urea, ammonium nitrate, dry ice tend to increase nuclei which increase the cloud density.

Cloud Seeding:

Final stage involves bombardment of super-cooled agents, silver iodide and dry ice which form large ice crystals & droplets of water and make them fall down in the form of rain. Airplanes are used to spray these agents on the clouds. As these agents are super-cooled , when they fall on the clouds they reduce the temperature of water inside the cloud which turns them into ice crystals. When these ice crystals become large in size, cloud is no longer able to hold them and they fall to earth in the form of small icy pellets. They usually melt and form rain when they fall on area where temperature is above zero degree Celsius.